Dependence of the efficiency of various emissions on excitation density in BaF2 crystals

The dependence of the intensity of the emission of self-trapped excitons, crossluminescence (CL) and intraband luminescence on the excitation density in BaF2 by electron pulses (300 keV, 3 ns) has been studied. The energy input above 2 x 10(19) eV cm(-3) causes quenching of 5.5 eV CL due to the recombination of conduction electrons with the outermost-core holes resulting in the formation of cation excitons and the subsequent energy transfer from a cation exciton to a valence electron of a neighbouring anion. The excitation spectra for various fast (tau < 5 ns) and inertial emissions have been measured using synchrotron radiation at 9 K. (C) 2001 Elsevier Science Ltd. All rights reserved.